Code review comment for ~lucaskanashiro/ubuntu/+source/heartbeat:fix-autopkgtest-regression

I think we should do the transitional package because there might be many stuff depending on resource-agents - like HA JuJu Charms - that might not have recommends installed automatically. By having the transitional package we would be making sure that we don't depend on end user setup for the upgrade to occur smoothly. There is also the benefit of allowing us to remove the virtual package in the next release, and still keep what end-user installed (if -supported only, as users of hirsute/groovy would have both -supported and -unsupported installed by the transitional package).